Sentinel lymph nodes in cancer of the oral cavity: is central step-sectioning enough?

A Systematic Review of Oral Biopsies, Sample Types, and Detection Techniques Applied in Relation to Oral Cancer Detection

Background: Early identification of the stage of oral cancer development can lead to better treatment outcomes and avoid malignant transformation. Therefore, this review aims to provide a comprehensive overview that describes the development of standardized procedures for oral sample collection, characterization, and molecular risk assessment. This can help investigators to choose the appropriate sampling method and downstream analyses for different purposes. Methods: This systematic review was conducted according to the PRISMA guidelines. Using both PubMed and Web of Science databases, four independent authors conducted a literature search between 15 and 21 June 2021. We used key search terms to broaden the search for studies. Non-conforming articles were removed using an EndNote-based and manual approach. Reviewers used a designed form to extract data. Results: This review included a total of 3574 records, after eliminating duplicate articles and excluding papers that did not meet the inclusion criteria. Finally, 202 articles were included in this review. We summarized the sampling methods, biopsy samples, and downstream analysis. The biopsy techniques were classified into tissue and liquid biopsy. The common sequential analysis of tissue biopsy includes histopathological examination such as H&E or IHC to identify various pathogenic features. Meanwhile, liquid samples such as saliva, blood, and urine are analyzed for the purpose of screening to detect mutations in cancer. Commonly used technologies are PCR, RT-PCR, high-throughput sequencing, and metabolomic analysis. Conclusions: Currently, tissue biopsies provide increased diagnostic value compared to liquid biopsy. However, the minimal invasiveness and convenience of liquid biopsy make it a suitable method for mass screening and eventual clinical adoption. The analysis of samples includes histological and molecular analysis. Metabolite analysis is rising but remains scarce.

Presentation and outcomes of patients with clinically T1-2, N0 supraglottic squamous cell carcinoma: The role of definitive radiotherapy compared to primary partial laryngectomy

BACKGROUND

Early-stage supraglottic squamous cell carcinoma (SCC) is usually treated with a single modality. The aim of this study is to examine the role of radiotherapy (RT) versus partial laryngectomy (open, robotic-assisted, or endoscopic) with elective neck dissection (PL + END).

METHODS

A retrospective analysis of the National Cancer Database, 2010-2016. The study population included adult patients with clinically T1-2, N0 supraglottic SCC.

RESULTS

3301 patients were included. RT was performed in 93.52%, open PL + END in 2.64%, robotic-assisted PL + END in 1.33%, and endoscopic surgical resection in 2.51%. In the surgery group, T was upstaged in 23.36% and N was upstage in 16.36%. Five-year survival in the primary surgery group compared to RT group was 61.89% versus 77.46% (HR: 0.56, 95%CI: 0.43, 0.72).

CONCLUSIONS

T was upstaged in 23% of surgical patients. This accurate staging is likely missed in patients who undergo RT and possibly contributes to lower overall survival of this treatment group.

Usefulness of Sentinel Lymph Node Biopsy for Oral Cancer: A Systematic Review and Meta-Analysis

OBJECTIVE

We assessed the diagnostic accuracy of sentinel lymph node biopsy (SLNB) for detecting neck nodal metastasis in early oral squamous cell carcinoma (OSCC) as an alternative to elective neck dissection.

STUDY DESIGN

A systematic search for relevant literature was conducted in the PubMed, SCOPUS, Embase, Web of Science, and Cochrane databases.

METHODS

Two reviewers individually searched the five databases up to November 2019. For studies that met inclusion criteria, data on patient diagnoses were pooled, including true positives, true negatives, false positives, and false negatives. Methodological quality was checked with the Quality Assessment of Diagnostic Accuracy Studies (version 2) tool.

RESULTS

In total, 98 observational or retrospective studies were included. The diagnostic odds ratio of SLNB was 326.165 (95% confidence interval [CI]: 231.477-459.587; I²  = 0%). The area under the summary receiver operating characteristic curve was 0.982. Sensitivity was 0.827 (95% CI: 0.804-0.848), and specificity was 0.981 (95% CI: 0.975-0.986). The correlation between sensitivity and the false positive rate was -0.076, which indicates that heterogeneity did not exist. Subgroup analyses were performed with the subgroups reference test type, publication year, and study type. No significant difference was found within the reference test type subgroup. However, differences within the publication year and study type subgroups were significant, where the retrospective study subgroup was significantly more sensitive and specific than the prospective study subgroup.

CONCLUSION

Results of this meta-analysis imply that the high specificity of SLNB supports its role as a diagnostic tool for patients with clinical tumor stage (CT)1-2 clinically negative (N0) OSCC. More studies should be done to further verify the results of this study.

LEVEL OF EVIDENCE

2a Laryngoscope, 131:E459-E465, 2021.

Utility and Practicality of Multi-level Sectioning and Upfront Unstained Slide Cutting in Head and Neck Biopsies: A Critical Analysis

Upfront interval sectioning (cutting unstained slides between H&E levels) is used at our institution for biopsies at all sites except the gastrointestinal tract. Very limited data exists in the literature for the need for interval sectioning, and we are aware of no data at all for the head and neck. Biopsies from the larynx, oral cavity, pharynx, and sinonasal tract at our institution have had 5 levels cut. Levels 1, 3, and 5 or levels 2 and 5 had been stained with hematoxylin and eosin (H&E), depending on the subsite, and the remaining slides saved for possible later use. We retrospectively evaluated the use of unstained slides at these sites for clinical utility and efficiency by analyzing 3 years of cases from 1/1/2014 to 12/30/2016. A cutoff of 10% utilization was considered justification for continued upfront unstained slide cutting. We collected 706 larynx, 572 oral cavity, 184 pharynx, and 85 sinonasal tract biopsies over 3 years. The overall rate of unstained slide usage was 18.2%. Usage rates were significantly different by site: 7.8% (55/706) for larynx, 21.9% (125/572) for oral cavity, 30.6% (26/85) for sinonasal tract and 40.8% (75/184) for pharynx (p < 0.0001). The most common stain ordered in the pharynx was p16 immunohistochemistry (59.7%), but it was Grocott methenamine silver staining in the larynx (74.5%), oral cavity (70.4%), and sinonasal tract (35.1%). Usage of unstained slides was lowest for the larynx, and review of the biopsies with unstained slides utilized showed that the lesion was present on the 3rd H&E level in all cases. Removing this practice would have translated to saving 1,378 unstained slides. Upfront interval sectioning makes practical sense for biopsies from most sites in the head and neck, especially the pharynx, but our data suggests it can reasonably be forgone at least for biopsies of the larynx.

Topographical distribution of sentinel nodes and metastases from T1-T2 oral squamous cell carcinomas

OBJECTIVE

The objective is to investigate the topographical distribution of sentinel nodes (SNs) and lymph node metastases in T1-2cN0 oral squamous cell carcinomas (OSCCs).

METHODS

The study entailed a prospective enrolment of 220 patients with clinical T1-2N0 OSCCs who underwent preoperative lymphoscintigraphy (LSG) followed by gamma probe-guided sentinel lymph node biopsy (SLNB). Patients with positive SNs were treated with completion neck dissection. Excised lymph nodes were grouped into the neck level according to the international guidelines.

RESULTS

The SN detection rate by LSG was 99.1%. Patients with midline tumours had bilateral lymphatic drainage on LSG in 15/21 (71.5%). There were 45/199 (22.6%) patients with lateralised tumours that had unexpected bilateral or contralateral drainage patterns on LSG. Fifty-five patients (25.0%) were SLNB positive, and metastases were found in 72/781 (9.2%) of the excised SNs. Metastatic involvement of neck level IV was rare and only observed in patients with anterior tongue cancer. No patients had level V involvement. Eleven patients developed isolated cervical recurrences, with no new primary tumour as origin. The SLNB procedure ensured an overall sensitivity of 83.3% and a negative predictive value of 93.3%.

CONCLUSION

Completion neck dissection of level I-III in SLNB-positive patients might be sufficient in most patients with OSCC except patients with anterior tongue cancer, but further studies are needed to support this potential therapeutic algorithm. Our study showed that SLNB was helpful in clarifying unexpected bilateral or contralateral metastatic drainage patterns. In our cohort, 8/55 patients with occult metastasis would have been missed by elective neck dissection of the ipsilateral neck.

A Multicenter Retrospective Study of Elective Neck Dissection for T1-2N0M0 Tongue Squamous Cell Carcinoma: Analysis Using Propensity Score-Matching

Background

This multicenter retrospective study aimed to determine whether elective neck dissection (END) can be performed for T1-2N0M0 tongue cancer.

Methods

Patients with T1-2N0M0 tongue squamous cell carcinoma who received treatment between January 2000 and December 2012 were enrolled at 14 multicenter study sites. The 5-year overall survival (OS) and 5-year disease-specific survival (DSS) were compared between the propensity score-matched END and observation (OBS) groups.

Results

The results showed that the OS rates among the 1234 enrolled patients were 85.5% in the END group and 90.2% in the OBS group (P = 0.182). The DSS rates were 87.0% in the END group and 94.3% in the OBS group (P = 0.003). Among the matched patients, the OS rates were 87.1% in the END group and 76.2% in the OBS group (P = 0.0051), and the respective DSS rates were 89.2% and 82.2% (P = 0.0335).

Conclusion

This study showed that END is beneficial for T1-2N0M0 tongue cancer. However, END should be performed for patients with a tumor depth of 4–5 mm or more, which is the depth associated with a high rate of lymph node metastasis. The use of END should be carefully considered for both elderly and young patients.

Diagnostic Efficacy of Sentinel Lymph Node Biopsy in Early Oral Squamous Cell Carcinoma: A Meta-Analysis of 66 Studies

OBJECTIVES

The diagnostic efficacy of sentinel lymph node biopsy(SLNB) in early oral squamous cell carcinoma(OSCC) still remains controversial. This meta-analysis was conducted to assess the diagnostic value of SLNB in clinically neck-negative T1-2 OSCC.

METHODS

A systematic literature search for relevant literature published up to September 11, 2016 was conducted in PubMed, Embase, Web of Science, Cochrane Library and ClinicalTrials, and the reference lists of eligible studies were examined. Data from different studies were pooled to estimate the summary sentinel lymph node(SLN) identification rate, sensitivity, negative predictive value. Summary receiver operator characteristic curve(SROC) was plotted and area under the SROC curve (AUC) was calculated to evaluate the overall diagnostic efficacy. Threshold effect was assessed with use of the spearman correlation coefficient. Between-study heterogeneity was tested using the Q tests and the I2 statistics. Subgroup analyses were conducted in view of the greater effect of different study characteristics on diagnostic efficacy of SLN. Deeks' funnel plot asymmetry test was performed to evaluate publication bias. Sensitivity analysis was evaluated through omitting studies one by one and comparing the pooled results of random-effects model and fixed-effects model. All analyses were performed using Review Manager (version 5.3.5), Meta-DiSc (version 1.4), Comprehensive Meta Analysis (version 2.0) and STATA (version 12).

RESULTS

66 studies comprising 3566 patients with cT1-2N0 OSCC were included in this meta-analysis. The pooled SLN identification rate was 96.3%(95% CI: 95.3%-97.0%). The pooled sensitivity was 0.87 (95% CI: 0.85-0.89), pooled negative predictive value was 0.94 (95% CI: 0.93-0.95), and AUC was 0.98 (95% CI: 0.97-0.99). Subgroup analyses indicated that SLN assessment with immunohistochemistry(IHC) achieved a significantly higher sensitivity than without IHC.

CONCLUSIONS

This meta-analysis suggests that SLNB has a high diagnostic accuracy in cT1-2N0 oral squamous cell carcinoma, and is an ideal alternative to elective neck dissection. Furthermore, the use of IHC can significantly improve SLNB diagnostic sensitivity for early OSCC.

Detection of cervical lymph node micrometastasis and isolated tumor cells in oral squamous cell carcinoma using immunohistochemistry and serial sectioning

INTRODUCTION

Oral squamous cell carcinoma (OSCC) comprises one of the largest subsets of cancers with a tendency for regional metastasis. Nodal status is a key prognostic indicator in patients with OSCC, particularly with N0 neck. Occult metastasis in the form of micrometastasis (MM) and isolated tumor cells (ITCs), often goes undetected by routine hematoxylin and eosin (H&E) examination using 1-2 sections for analysis. This limitation could be overcome by combining serial sectioning (SS) with immunohistochemistry (IHC) for the detection of MM and ITC. Pan-cytokeratin (pan-CK) (AE1/AE3) is particularly a useful marker to detect these deposits as their presence has resulted in varied interpretations and different applications of the tumor-node-metastasis system.

OBJECTIVES

The objective of the study was to identify a suitable method for detecting MM and ITC in lymph nodes (LNs) of OSCC by combining SS and IHC and to compare it with conventional H&E staining.

MATERIALS AND METHODS

This laboratory-based, prospective study was conducted on 133 LNs harnessed from ten patients treated with radical neck dissection for primary OSCC. The LNs were subjected to SS at 100 μm intervals. The sections were stained with routine H&E staining, pan-CK and analyzed for MM and ITC according to criteria laid by Hermanek et al.

STATISTICAL ANALYSIS

The obtained data were subjected to statistical analysis using Chi-square test.

RESULTS

The application of combination of SS and IHC using pan-CK (AE1/AE3) in our study revealed the presence of MM and ITC in 2.25% of the LNs diagnosed as negative on routine H&E examination. The detection of these occult metastatic deposits resulted in upstaging of 33.33% of the patients.

CONCLUSION

In the view of crucial role of occult LN metastasis in prognosis and survival of OSCC patients with N0 neck, diagnostic tools such as IHC staining, particularly with pan-CK (AE1/AE3), combined with SS should be preferred over conventional methods as they result in upstaging, thus sparing the low-risk patients the morbidity of unnecessary treatment.

Accuracy of microRNAs as markers for the detection of neck lymph node metastases in patients with head and neck squamous cell carcinoma

BACKGROUND

The presence of metastatic disease in cervical lymph nodes of head and neck squamous cell carcinoma (HNSCC) patients is a very important determinant in therapy choice and prognosis, with great impact in overall survival. Frequently, routine lymph node staging cannot detect occult metastases and the post-surgical histologic evaluation of resected lymph nodes is not sensitive in detecting small metastatic deposits. Molecular markers based on tissue-specific microRNA expression are alternative accurate diagnostic markers. Herein, we evaluated the feasibility of using the expression of microRNAs to detect metastatic cells in formalin-fixed paraffin-embedded (FFPE) lymph nodes and in fine-needle aspiration (FNA) biopsies of HNSCC patients.

METHODS

An initial screening compared the expression of 667 microRNAs in a discovery set comprised by metastatic and non-metastatic lymph nodes from HNSCC patients. The most differentially expressed microRNAs were validated by qRT-PCR in two independent cohorts: i) 48 FFPE lymph node samples, and ii) 113 FNA lymph node biopsies. The accuracy of the markers in identifying metastatic samples was assessed through the analysis of sensitivity, specificity, accuracy, negative predictive value, positive predictive value, and area under the curve values.

RESULTS

Seven microRNAs highly expressed in metastatic lymph nodes from the discovery set were validated in FFPE lymph node samples. MiR-203 and miR-205 identified all metastatic samples, regardless of the size of the metastatic deposit. Additionally, these markers also showed high accuracy when FNA samples were examined.

CONCLUSIONS

The high accuracy of miR-203 and miR-205 warrant these microRNAs as diagnostic markers of neck metastases in HNSCC. These can be evaluated in entire lymph nodes and in FNA biopsies collected at different time-points such as pre-treatment samples, intraoperative sentinel node biopsy, and during patient follow-up. These markers can be useful in a clinical setting in the management of HNSCC patients from initial disease staging and therapy planning to patient surveillance.

Gene expression analysis of SCC tumor cells in muscle tissue

The purpose of this study was to evaluate microarray technology of HNSCC cells in muscle tissue. 200 SCCVII tumor cells were injected intramuscularly into the right flank of ten C3H/Km mice each. One week later the animals were killed and the tissue taken out. Histology (H&E staining) and microarray of the tissue were performed. Histology showed a few tumor cells between the muscle fibers. Microarray technology showed different gene expression pattern of the muscle tissue with SCCVII cells in comparison with normal muscle tissue. Only those genes showing a fold change difference of 5 or higher were considered. Gene expression analysis revealed changes in the expression levels of SCCVII cells in muscle tissue in 220 genes. Significant gene expression differences between SCCVII cells in muscle tissue and pure muscle tissue could be seen.

Detection of metastatic head and neck squamous cell carcinoma using the relative expression of tissue-specific mir-205

The presence of cervical lymph node metastases in head and neck squamous cell carcinoma (HNSCC) is the strongest determinant of patient prognosis. Owing to the impact of nodal metastases on patient survival, a system for sensitive and accurate detection is required. Clinical staging of lymph nodes is far less accurate than pathological staging. Pathological staging also suffers limitations because it fails to detect micrometastasis in a subset of nodal specimens. To improve the sensitivity of existing means of diagnosing metastatic disease, many advocate the use of molecular markers specific for HNSCC cells. MicroRNA (miRNA) are short noncoding segments of RNA that posttranscriptionally regulate gene expression. Approximately one third of all miRNA will exhibit substantial tissue specificity. Using a quantitative reverse transcription-polymerase chain reaction-based assay, we examined the expression of microRNA-205 (mir-205) across tissues and demonstrated that its expression is highly specific for squamous epithelium. We applied this assay to tissue samples, and we could detect metastatic HNSCC in each positive lymph node specimen, whereas benign specimens did not express this marker. When compared to metastases from other primary tumors, HNSCC-positive lymph nodes were distinguishable by the high expression of this marker. Using an in vitro lymphoid tissue model, we were able to detect as little as one squamous cell in a background of 1 million lymphocytes. By combining the sensitivity of quantitative reverse transcription-polymerase chain reaction with the specificity of mir-205 for squamous epithelium, we demonstrate a novel molecular marker for the detection of metastatic HNSCC.

Joint practice guidelines for radionuclide lymphoscintigraphy for sentinel node localization in oral/oropharyngeal squamous cell carcinoma

Involvement of the cervical lymph nodes is the most important prognostic factor for patients with oral/oropharyngeal squamous cell carcinoma (OSCC), and the decision whether to electively treat patients with clinically negative necks remains a controversial topic. Sentinel node biopsy (SNB) provides a minimally invasive method of determining the disease status of the cervical node basin, without the need for a formal neck dissection. This technique potentially improves the accuracy of histological nodal staging and avoids over-treating three-quarters of this patient population, minimizing associated morbidity. The technique has been validated for patients with OSCC, and larger-scale studies are in progress to determine its exact role in the management of this patient population. This article was designed to outline the current best practice guidelines for the provision of SNB in patients with early-stage OSCC, and to provide a framework for the currently evolving recommendations for its use. These guidelines were prepared by a multidisciplinary surgical/nuclear medicine/pathology expert panel under the joint auspices of the European Association of Nuclear Medicine (EANM) Oncology Committee and the Sentinel European Node Trial Committee.

Joint Practice Guidelines for Radionuclide Lymphoscintigraphy for Sentinel Node Localization in Oral/Oropharyngeal Squamous Cell Carcinoma

Involvement of the cervical lymph nodes is the most important prognostic factor for patients with oral/oropharyngeal squamous cell carcinoma (OSCC), and the decision of whether to electively treat patients with clinically negative necks remains a controversial topic. Sentinel node biopsy (SNB) provides a minimally invasive method for determining the disease status of the cervical node basin, without the need for a formal neck dissection. This technique potentially improves the accuracy of histologic nodal staging and avoids overtreating three-quarters of this patient population, minimizing associated morbidity. The technique has been validated for patients with OSCC, and larger-scale studies are in progress to determine its exact role in the management of this patient population. This document is designed to outline the current best practice guidelines for the provision of SNB in patients with early-stage OSCC, and to provide a framework for the currently evolving recommendations for its use. Preparation of this guideline was carried out by a multidisciplinary surgical/nuclear medicine/pathology expert panel under the joint auspices of the European Association of Nuclear Medicine (EANM) Oncology Committee and the Sentinel European Node Trial (SENT) Committee.

Head and neck sentinel lymph node biopsy: current state of the art

Sentinel node biopsy is an alternative to elective neck dissection for the management of T1/T2 oral and oro-pharyngeal squamous cell carcinomas and is also finding application to head and neck cancer at other sites. The main clinical aim of sentinel node biopsy is to achieve better staging and there is now evidence that the procedure reduces morbidity. Reported detection rates for sentinel neck nodes are greater than 95% and there is also a negative predictive value of 95% for negative sentinel nodes. Current histopathological protocols have been developed for use in the research setting and are designed to identify all micrometastatic disease. However the use of step serial sectioning at 150 micron intervals with pan-cytokeratin immunohistochemistry is currently advised and appears to upstage nodes by approximately 20% over the initial single routine stained section. Adoption of the UICC/TNM definitions is recommended for future sentinel node studies, but further refinements and descriptions are required. The SENT trial has recruited over 300 cases from 10 European centres and a quality control study of the pathological material is in progress. At the first consensus meeting of the SENT pathology group there were excellent levels of agreement on the diagnosis of positive and negative nodes, and a number of potential pitfalls such as non-malignant inclusions and staining artefacts were identified.

Micrometastases and isolated tumour cells in sentinel lymph nodes in oral and oropharyngeal squamous cell carcinoma

BACKGROUND

The occurrence of micrometastases (MMs) and isolated tumour cells (ITCs) in oral sentinel lymph node (SLN) biopsy is poorly known, and the definitions and clinical significance of MMs and ITCs in SLN biopsy are controversial. We compared the UICC/TNM definitions of MMs and ITCs with our previously published sentinel node protocol to assess how the adoption of the UICC/TNM criteria would affect the staging of nodal micrometastatic disease.

METHODS

Of 107 patients who had a SLN biopsy and pathology at 150 microm intervals, 35 with metastatic tumour were included. Eighty-six SLNs were reassessed using the UICC/TNM definitions for MMs and ITCs. Findings were linked to the final pathology in the subsequent neck dissection.

RESULTS

Initial H&E sections showed metastases in 24 patients (in 34 out of 61 SLN), 8 of whom (9 SLNs) had MMs. Additional step serial sections revealed metastatic deposits in a further 11 patients (15 out of 25 SLNs were positive) which were reassessed as MMs (6 patients) or ITCs (5 patients). Subsequent neck dissection revealed additional metastases in 46% of patients with MM, whilst one of the ITC patients had subsequent neck metastases (20%).

CONCLUSION

Despite some limitations, the UICC/TNM classification provides an objective, uniform method of detecting MMs and ITC's. Unlike in cases with ITC, metastases in other non-SLNs were common when a micrometastasis was detected in a SLN, indicating need for further treatment of the neck.

Detection of lymph node micrometastases in patients with squamous carcinoma of the head and neck

While the significance of large cervical node metastases in patients with head and neck squamous carcinomas is well established, the import of a finding of regional nodal micrometastases (where a micrometastasis is defined as a metastatic deposit greater than 0.2 mm and not greater than 2.0 mm in greatest dimension) or isolated tumor cells in those patients is less clearly understood. Some earlier investigators have suggested that finding micrometastases does not have an impact on prognosis; some later investigators, however, have taken issue with this position, arguing that finding either micrometastases or isolated tumor cells might portend a poorer prognosis for head and neck cancer patients. At this juncture, it is difficult to advance a single recommendation for handling a finding of micrometastases or isolated tumor cells. It would be helpful if two courses of action were followed: first, while the detection of micrometastases and isolated tumor cells remains an investigatory practice, data should be collected and analyzed with an eye to discerning whether such findings are indeed of significance to the individual head and neck cancer patient. Second, rigorous definitions of micrometastases and isolated tumor cells (such as the definitions suggested here) should be developed and widely employed so as to permit ready comparison between the results as they are reported by different investigators.